Americans this year are marking the 20th anniversary of the Americans with Disability Act - also called the ADA - a civil rights law that prohibits discrimination based on mental or physical disabilities. One event in the celebration was a recent film Festival which highlighted a documentary film called "Unbeaten," a story about the world's longest and toughest wheelchair race.

Racing in a wheelchair is challenging enough. But racing 430 kilometers, through mountains, would seem to be nearly impossible. That is why 57-year-old Geoffrey Erickson wanted to participate. "It is kind of funny. When I got out of the hospital, people were trying to tell me what I couldn't do and just setting up limits all over the places," he says, "You got kind of maddening."

Erickson has been determined to overcome those limits ever since a motorcycle accident put him in a wheelchair 33 years ago. He is one of the main characters in the film.

Unbeaten follows 31 paraplegics for six days - as they compete in wheelchairs and hand cycles in what is known as the toughest road race in the world. The course winds 430 kilometers through the mountain passes between Fairbanks and Anchorage, Alaska.

"When I was pushing up the hill, it was just painful," he says, "I had to just try to stay focused. It was just brutal. I still can remember the pain. I hurt my shoulders and the back, my arms, everywhere."

The film takes viewers along as the racers grind out some 88 kilometers per day

For many of the participants, it is a journey of self-discovery, of strength and a demonstration of will and determination.

Midway through, the film shifts its focus, as the filmmaker follows the elite racers of the U.S. Paralympics squad in their quest to medal at the 2008 Beijing Paralympics. Oscar "Oz" Sanchez, a US Marine veteran who served in Iraq and Afghanistan, is a current Paralympics gold medalist.

Oscar 'Oz' Sanchez, a US Marine veteran who served in Iraq and Afghanistan, is the current Paralympics gold medalist.

"Being a gold medalist and being a world champion, it sets a standard that what you believe you can achieve no matter what is your alleged limitations are. Just because you have a disability does not mean your goals and your dreams have to change," Sanchez said. "You just find a different means to attain those goals. That's all."

Filmmaker and director Steven C. Barber says it was a three-year odyssey to finish the documentary. "We think somebody in a wheelchair is helpless and it is absolutely the opposite. I mean 55 miles [88.5 kilometers] a day in a wheelchair, that's amazing even though these guys are the elite, elite of the wheelchair world. People in wheelchairs don't have disabilities, they actually have ability," he said. "I learned that just because somebody is in a wheelchair doesn't mean that they are disabled."

Barber says Unbeaten is both a tribute to heroism and a message of hope to countless disabled individuals worldwide. He says the paraplegics show the world what can be done, and that the words "disabled and "obstacle" are only that… words.